I had three college classes that really sealed this up for me: linear algebra, a set theory 'light' class, and a class on database mechanics itself. After than

I had three college classes that really sealed this up for me: linear algebra, a set theory 'light' class, and a class on database mechanics itself. After than I was able to reason about mathematical sets, and scalar functions and what the database engine is doing. If you "just learn SQL" without understanding the abstraction below it, it'll be difficult to be successful, much the same with anything else.